U.S. patent application number 16/425545 was filed with the patent office on 2019-12-12 for cooling ring bracket.
The applicant listed for this patent is Siemens Gamesa Renewable Energy A/S. Invention is credited to Tom Quist.
Application Number | 20190376561 16/425545 |
Document ID | / |
Family ID | 62562982 |
Filed Date | 2019-12-12 |
![](/patent/app/20190376561/US20190376561A1-20191212-D00000.png)
![](/patent/app/20190376561/US20190376561A1-20191212-D00001.png)
![](/patent/app/20190376561/US20190376561A1-20191212-D00002.png)
![](/patent/app/20190376561/US20190376561A1-20191212-D00003.png)
![](/patent/app/20190376561/US20190376561A1-20191212-D00004.png)
United States Patent
Application |
20190376561 |
Kind Code |
A1 |
Quist; Tom |
December 12, 2019 |
COOLING RING BRACKET
Abstract
Provided is a bracket for securing a number of cooling rings
arranged on a bearing ring, which bracket includes an upper
surface, a lower surface shaped to lie on the cooling rings, and a
through-opening extending between the upper surface and the lower
surface to accommodate a fastener for mounting the bracket to the
bearing ring; wherein the material properties of the bracket are
chosen to permit movement of the cooling rings relative to the
bracket when the bracket is mounted to the bearing ring; and/or
wherein the bracket is made of a resilient elastic material.
Further provided is a cooling arrangement for a bearing, including
a number of cooling rings arranged in parallel on a mounting
surface of a bearing ring of the bearing; and a number of such
brackets to secure the cooling rings to the bearing body.
Inventors: |
Quist; Tom; (Silkeborg,
DK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Siemens Gamesa Renewable Energy A/S |
Brande |
|
DK |
|
|
Family ID: |
62562982 |
Appl. No.: |
16/425545 |
Filed: |
May 29, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16C 43/04 20130101;
F16C 2300/54 20130101; F28F 2275/08 20130101; F03D 80/60 20160501;
F16C 37/007 20130101; F05B 2260/30 20130101; F05B 2240/50 20130101;
F03D 15/20 20160501; F16C 33/64 20130101; F16C 37/00 20130101; F28F
9/013 20130101; F03D 80/70 20160501; F16C 2300/14 20130101; F16C
2360/31 20130101; F16L 3/04 20130101; F16C 33/586 20130101; F16L
3/2235 20130101; F28F 2275/20 20130101; F28F 1/04 20130101; F28D
2021/0029 20130101; F16C 2226/76 20130101 |
International
Class: |
F16C 43/04 20060101
F16C043/04; F16C 37/00 20060101 F16C037/00; F16C 33/58 20060101
F16C033/58; F16C 33/64 20060101 F16C033/64 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 6, 2018 |
EP |
18176279.0 |
Claims
1. A bracket for securing a number of cooling rings arranged on a
bearing ring, which bracket comprises a lower surface shaped to lie
on the cooling rings, and a through-opening extending between an
upper surface and the lower surface to accommodate a fastener for
mounting the bracket to the bearing ring; wherein the material
properties of the bracket are chosen to at least one of: a) permit
movement of the cooling rings relative to the bracket when the
bracket is mounted to the bearing ring; and b) wherein the bracket
is made of a resilient elastic material.
2. The bracket according to claim 1, made of polyoxymethylene.
3. The bracket according to claim 1, wherein the length of the
through-opening exceeds the height of a cooling ring by at least
one of at least 200% or at least 250%.
4. The bracket according to claim 1, wherein the bracket is shaped
to transfer at least one of at least 15%, or at least 30% of the
force exerted by the fastener onto each cooling ring.
5. The bracket according to claim 1, shaped to span at least three
cooling rings.
6. The bracket according to claim 1, wherein the through-opening is
formed such that the fastener extends into a gap between adjacent
cooling rings when the bracket is mounted to the bearing ring.
7. The bracket according to claim 1, comprising a nose arranged to
extend into a gap between adjacent cooling rings.
8. The bracket according to claim 1, comprising a nose shaped to
extend over an outer edge of an outer cooling ring.
9. The bracket according to claim 1, comprising an attachment
realized to facilitate attachment of an object to the bracket.
10. A cooling arrangement for a bearing, comprising a number of
cooling rings arranged in parallel on a mounting surface of a
bearing ring of the bearing; and a number of brackets according to
claim 1, wherein a bracket is arranged to span the cooling rings
and is secured to the bearing ring by a fastener extending from the
upper surface of the bracket through the through-opening and into
the bearing body.
11. The cooling arrangement according to claim 10, wherein the
fastener is a metal screw comprising a flanged head, a shank and a
threaded portion, wherein the length of the shank is at least the
length of the through-opening.
12. The cooling arrangement according to claim 11, wherein the
flanged head is ridged to engage with the material of the
bracket.
13. The cooling arrangement according to claim 10, wherein a
cooling ring is realized as a metal conduit with a rectangular
cross-section and a height in the region of 15 mm-30 mm.
14. The cooling arrangement according to claim 10, comprising at
least one set of three cooling rings secured to the bearing ring by
a plurality of brackets (1).
15. A main bearing of a direct-drive wind turbine generator,
comprising a cooling arrangement according to claim 10 to cool the
bearing.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to EP Application No.
18176279.0, having a filing date of Jun. 6, 2018, the entire
contents of which are hereby incorporated by reference.
FIELD OF TECHNOLOGY
[0002] The following describes a cooling ring bracket, and a
cooling arrangement.
BACKGROUND
[0003] Large bearings are required in various applications such as
large electrical machines. A main bearing of a generator such as a
multi-megawatt wind turbine generator can have a diameter of
several meters. During operation, a rotating bearing ring turns
relative to a stationary bearing ring, and it is generally
unavoidable that heat develops during operation, so that large
bearings require some kind of cooling arrangement.
[0004] One way of cooling such a large bearing is to arrange a
number of hollow annular channels or "cooling rings" about the
stationary bearing ring, and to transport a fluid cooling medium
through these channels. A cooling circuit is completed by
connecting the cooling rings by means of hoses to a pump that
circulates a fluid coolant through the channels. A thermal
conductive paste can be applied between the bearing surface and the
cooling ring to improve heat transfer. Usually, the cooling rings
are made of aluminium or a similar metal that is effective in
transporting heat.
[0005] To cool the bearing effectively, the channels must be
pressed against the body of the bearing so that heat from the
bearing can be transferred to the cooling medium. This has usually
been achieved by arranging a flat metal bracket or clamp across
several parallel cooling rings, and screwing the metal bracket into
the body of the bearing using a fastener. The clamping effect is
achieved by tightening the fastener to a sufficient tension.
[0006] However, the effectiveness of the known bracket realization
is compromised by several factors such as vibrations in the
bearing; thermal expansion and contraction of the cooling rings,
brackets and fasteners; ovalization of the bearing, etc. Any of
these factors can cause the fastener to become loose eventually. A
loosened fastener means or fastener that the cooling rings are no
longer effectively pressed against the bearing surface. The usual
way to address this problem is to tighten the fastener as much as
possible, but this generally only has the effect of gradually
forcing the thermal paste from underneath the cooling rings, and
the fastener can then become loose. Another way of addressing this
problem might be to use more fasteners, for example two fasteners
per bracket. However, this would be associated with considerable
costs since it is then necessary to machine a large number of
additional threaded bushings in the bearing ring, in addition to
the added material costs of the additional fasteners, washers,
etc.
[0007] Another problem with the known bracket is that a cold weld
can form between the opposing surfaces of the metal bracket and
metal cooling ring, particularly when these are made of the same
metal. Cold welds are made more likely when great force is used to
tighten the fasteners. Slight back-and-forth movements
(micro-movements) of a cooling ring may ensue from any of the
factors listed above, but a cold weld between a cooling ring and a
bracket will act to allow motion in one direction only. As a
result, a cooling ring may exhibit a creeping motion in that
direction. As explained above, a hose is attached at some point to
a cooling ring in order to circulate the fluid coolant, but the
creeping movement of the cooling ring may ultimately cause failure
at the hose connection point. A cold weld is more likely to form
between two objects made of the same metal, but even if the bracket
is made of a metal that is different from the metal of the cooling
rings to avoid the formation of cold welds, this would not solve
the problem of the fasteners becoming loose.
SUMMARY
[0008] An aspect relates to provide an improved way of securing
cooling rings to a bearing ring, to overcome the problems outlined
above.
[0009] According to embodiments of the invention, the cooling ring
bracket secures a number of cooling rings arranged in parallel on a
surface of a bearing ring of a large bearing, and is shaped to
extend over several cooling rings and comprises an upper surface, a
lower surface shaped to lie on the cooling rings, and a
through-opening extending from the upper surface to the lower
surface to accommodate a fastener for mounting the bracket to the
bearing ring. Generally, the upper and lower surfaces of the
bracket are essentially parallel and planar. The inventive bracket
is based on the insight that micro-movements of the cooling rings
are unavoidable, and the material properties of the bracket are
therefore chosen to permit lateral or sideways movement of the
cooling rings relative to the bracket when the bracket is mounted
to the bearing ring, i.e. the under surface of the bracket will
exhibit a low coefficient of friction when the system is at rest
(static friction) and also when the system is in motion (kinetic
friction). The "system" is to be understood as the cooling rings
and the brackets holding them in place, so that kinetic friction
applies when a cooling ring is moving slightly relative to a
bracket. The static friction .mu..sub.s between the cooling ring
surface(s) and the bracket is less than 0.45, or less than 0.3, in
contrast to the known art system, in which the static friction
.mu..sub.s between the aluminium cooling rings and an aluminium
bracket can exceed 1.5. According to embodiments of the invention,
the bracket is made of an elastic and resilient material, so that
the bracket will advantageously retain its shape even after being
subject to compression forces exerted on it by the fastener. Such
compression forces may arise when the cooling ring(s) undergo
thermal expansion. The material of the inventive bracket permits
some degree of compression and assumes its original shape when the
cooling rings once again undergo thermal contraction.
[0010] According to embodiments of the invention, the cooling
arrangement is realized to cool a large bearing of the type
described in the introduction, and comprises a number of cooling
rings arranged in parallel on a mounting surface of a bearing ring
of the bearing and a number of such brackets, wherein a bracket is
arranged to span the cooling rings and is secured to the bearing
ring by a fastener, a single fastener, extending from the upper
surface of the bracket through the through-opening and into the
bearing body.
[0011] An advantage of the inventive cooling arrangement is that
slight movements of the cooling rings relative to the bracket are
not prevented but instead, these micro-movements are deliberately
allowed. Instead of clamping a bracket onto cooling rings with
great force to lock the cooling rings in place, the inventive
bracket is designed to permit the cooling rings to move slightly
during operation of the bearing. As a result, the cooling rings can
move if required during operation of the bearing, and can return to
their original position. The likelihood of damage to any hoses of a
cooling circuit will therefore be reduced or even eliminated.
Another advantage of the inventive cooling arrangement is that the
bracket retains its shape even after being subject to compression
forces exerted on it by the fastener. Therefore, the effectiveness
of the bracket will not be compromised by factors such as
vibrations in the bearing, thermal expansion of the cooling rings,
ovalization of the bearing, etc.
[0012] A cold weld will not develop between a cooling ring and the
bracket when the material properties of the bracket are chosen to
exhibit low kinetic friction when the cooling ring moves relative
to the bracket.
[0013] Thermal expansion of the cooling rings will result in a
slight compression of the bracket body instead of loosening the
fastener. Owing to the resilience of the bracket material, the
bracket will assume its original shape following thermal
contraction of the cooling rings. The bracket fasteners of the
inventive cooling arrangement are therefore considerably less
likely to become loose during operation of the bearing.
[0014] Particularly advantageous embodiments and features of
embodiments of the invention are given by the dependent claims, as
revealed in the following description. Features of different claim
categories may be combined as appropriate to give further
embodiments not described herein.
[0015] The inventive bracket can be used to attach cooling rings to
any kind of large bearing. In the following, without restricting
embodiments of the invention in any way, it may be assumed that the
bearing is a main bearing of an electrical machine such as a
generator of a wind turbine. It may also be assumed that the outer
bearing ring rotates relative to the inner stationary bearing ring,
and that several cooling rings or cooling rings are arranged in
parallel on an inner surface of the stationary bearing ring.
[0016] Because it is generally exemplary to avoid expensive and
time-consuming modifications to a bearing in order to attach other
components, the cooling rings are generally shaped to lie on the
unaltered bearing surface. Therefore, in the following, a cooling
ring may be assumed to be a hollow metal conduit with a rectangular
cross-section, although other forms are possible. A cooling ring
can have a height of 15-30 mm, and a width in the order of 30 mm.
The cooling arrangement may be realized to circulate a suitable
coolant such as a mixture of ethylene glycol and water through the
cooling rings. For a large main bearing, one or more groups of
three or more parallel cooling rings may be used to cool the
bearing. The interior dimensions of a cooling ring are generally
chosen to achieve a satisfactory pressure and flow rate of the
cooling fluid. The inventive bracket may also be referred to in the
following as a cooling ring bracket, since it serves to hold the
cooling rings in place on the bearing.
[0017] A main bearing of a wind turbine generator can be realized
as a roller bearing. According to embodiments of the invention, the
main bearing of a wind turbine generator comprises a rotating outer
bearing ring and a stationary inner bearing ring, and an embodiment
of the inventive cooling arrangement installed on an inner annular
surface of the stationary bearing ring.
[0018] The cooling ring bracket can be made of any suitable
material, i.e. any material that exhibits the desired properties of
elasticity and resilience. In a particularly exemplary embodiment
of the invention, a bracket is made of polyoxymethylene (POM), POM
copolymer (POM-C), since this material exhibits a favourably high
degree of elasticity and a favourably high degree of resilience.
This material exhibits a very low coefficient of friction against
the surface of a metal (e.g. aluminium) cooling ring.
[0019] Furthermore, polyoxymethylene is a relatively cheap
material, and a polyoxymethylene bracket can be manufactured very
economically in an injection moulding process.
[0020] The bracket is formed so that, when the bracket is being
mounted to the bearing ring, a fastener inserted into the
through-opening will extend through a gap between adjacent cooling
rings. The body of the bracket is shaped to span at least three
cooling rings mounted in parallel on a bearing ring.
[0021] To effectively clamp the cooling rings against the surface
of the bearing ring, the clamping force exerted by the fastener
(when screwed into the bearing ring) is distributed over the
cooling rings. To this end, in a particularly exemplary embodiment
of the invention, the bracket is shaped such that, when mounted in
place over the cooling rings, the height of its upper surface (and
therefore also the fastener flange) exceeds the height of a cooling
ring by at least 200%, more at least 250%, and may even exceed the
height of a cooling ring by 300% or more. The added height
advantageously acts to better distribute the clamping force over
the cooling rings. The through-opening in the bracket is formed to
accommodate a fastener comprising a long shank or grip length. The
shank is the portion of the fastener between its threaded end and
the nut end. A standard fastener can be chosen to have a shank
length that is at least as long as the height of the bracket, so
that the threaded portion of the fastener does not extend into the
through-opening of the bracket. For example, for cooling rings with
a height of 15 mm, and a bracket with a height (i.e. through-hole
length) of 30 mm, the fastener shank length is at least 30 mm and
up to 45 mm. The length of the threaded portion is at least as long
as the depth of the threaded bushing machined in the bearing
ring.
[0022] The bracket and through-opening are formed so that the head
of the fastener lies against the upper surface of the bracket. The
fastener may have a conventional hexagonal head, for example. When
the fastener is screwed into the bearing ring so that the fastener
head presses onto the bracket, the resulting clamping force will be
distributed through the bracket body onto the cooling rings. The
clamping force generated when the inventive bracket is mounted onto
the cooling rings can be in the order of 4000 N. Due to the shape
and material properties of the inventive bracket, at least 15% of
this clamping force will be transferred to the outermost cooling
ring, and this clamping force will be maintained, since the
fastener will not become loose. In contrast, the shape and material
properties of a known art bracket result in loosening of the
fastener so that eventually there may be a complete absence of
clamping force acting on the cooling rings.
[0023] The fastener is a metal screw comprising a flanged head to
more effectively transfer the clamping force into the bracket. The
flange comprises a ridged or other surface texture so that the
flange acts as a lock washer to engage with the material of the
bracket. An advantage of the inventive bracket is that it can be
secured to the bearing ring using only a single fastener, without
the need for any additional washers, lock washers, spacers,
etc.
[0024] A known bracket could be secured to the bearing ring using a
fastener with a long shaft, but this would require the use of a
spacer to achieve the desired height above the cooling rings, as
well as several washers. While the use of a spacer with the known
flat bracket can improve the distribution of the clamping force
over the cooling rings, it does not solve the problem of cold welds
developing between the bracket and cooling ring, and may even
exacerbate this problem and the attendant likelihood of damage to a
cooling hose. It also does not solve the problem of fasteners
eventually becoming loose, so that the fasteners must be
re-tightened at regular intervals. Therefore, this approach is not
satisfactory on account of the significant costs associated with
the additional parts, together with the costs associated with
maintenance procedures.
[0025] The under surface of the bracket can be flat and uniform,
apart from the lower aperture of the through-opening. However, in
an exemplary embodiment of the invention, the bracket is formed to
comprise a nose arranged to extend into a gap between adjacent
cooling rings. The bracket may also be formed to comprise another
nose shaped to extend over an outer edge of an outer cooling ring.
A nose is formed as a ridge that extends over the depth of the
bracket, so that the nose fills the gap between adjacent cooling
rings, for example. Such a nose can also act as a spacer during the
assembly process when mounting the cooling rings onto the main
bearing. In the case of three or more parallel cooling rings, the
fastener will extend between two adjacent cooling rings, and the
nose(s) can contribute to an optimal distribution of the clamping
forces onto the cooling rings.
[0026] As mentioned above, a main bearing can become hot during
operation, and it is necessary to monitor the temperature. Also,
vibrations can develop during operation of the machine that
incorporates the bearing. Vibrations should also be monitored to
detect any anomaly. Temperature and/or vibrations can be measured
using various types of sensor. These need to be arranged close to
the source of heat/vibration. In an exemplary embodiment of the
invention, therefore, the bracket is formed to comprise an
attachment means or attachment realized to facilitate attachment of
a sensor cable to the bracket. The attachment means or attachment
can be an integral eyelet or short spar to which a cable tie can be
attached, for example.
BRIEF DESCRIPTION
[0027] Some of the embodiments will be described in detail, with
reference to the following figures, wherein like designations
denote like members, wherein:
[0028] FIG. 1 shows an embodiment of the inventive bracket;
[0029] FIG. 2 shows a perspective view of the cooling ring bracket
of FIG. 1;
[0030] FIG. 3 shows a perspective view of the cooling ring bracket
of FIGS. 1 and 2;
[0031] FIG. 4 shows a portion of a main bearing;
[0032] FIG. 5 shows a known bracket;
[0033] FIG. 6 illustrates a problem associated with the known
bracket of FIG. 5;
[0034] FIG. 7 shows another possible embodiments of the inventive
bracket that is shaped to span four cooling rings;
[0035] FIG. 8 shows another embodiment of the inventive bracket
that is shaped so that the through-hole is arranged to one side of
the bracket;
[0036] FIG. 9 shows another embodiment of the inventive bracket
which is shaped to span several cooling rings R1, R2, R3, and the
through-hole extends sideways through the bracket.
[0037] In the diagrams, like numbers refer to like objects
throughout. Objects in the diagrams are not necessarily drawn to
scale.
DETAILED DESCRIPTION
[0038] FIG. 1 shows an embodiment of the inventive bracket 1. The
bracket 1 is formed in one piece, for example, by injection
molding, and is realized to extend across three parallel cooling
rings R1, R2, R3. The body of the bracket 1 is roughly in the shape
of an acute trapezoid, and its highest point is positioned over a
gap G between two adjacent cooling rings R1, R2. The bracket 1
essentially extends from a base level 10 to an upper level 11, and
its shape is defined by an inclined side face extending from the
base level 10 to the upper level 11. The bracket is made of a
material that is highly resilient and which also exhibits a
favourable degree of elasticity and resilience so that it assumes
its original shape after being subject to compression. A suitable
choice of material may be a high performance engineering polymer
such as polyoxymethylene (POM-C) on account of its strength,
elastic modulus, and longevity. The static friction .mu..sub.s
between the surface of an aluminium cooling ring R1, R2, R3 and a
POM-C bracket 1 can be very low, e.g. lower than 0.3, so that the
bracket 1 will not inhibit a micro-movement of the cooling ring R1,
R2, R3 during operation of the bearing.
[0039] In this embodiment, a through-opening 14 extends through the
bracket 1 from the upper level 11 to the base level 10, so that a
fastener 4 can be screwed into a threaded bushing 30B in the
bearing ring 30. Here, the fastener 4 is a metal screw with a head
40 and an integrally formed flange 400, so that the flange 400 lies
against the upper surface 11 of the bracket 1. When the fastener 4
is tightened, a clamping force F is transferred via the flange 400
through the body of the bracket 1 and onto the cooling rings R1,
R2, R3, specifically also onto the outermost cooling ring R3, even
though this is offset laterally from the fastener 4. In this
exemplary embodiment using a bracket 1 made of POM-C, the torque
applied when tightening the fastener should not exceed 25 Nm, which
is large enough to achieve the desired clamping force onto the
cooling rings. The favourably uniform transfer of force F is made
possible by the specific shape of the cooling ring bracket 1 and
also by its properties of elasticity and resilience. A serrated
flange surface ensures that the flange 400 engages with the
material of the bracket 1 in the manner of a lock washer.
[0040] The diagram also indicates a layer of thermal paste P
between the bearing ring 30 and the cooling rings R1, R2, R3. The
purpose of the paste P is to facilitate the transfer of heat
between the bearing and the cooling rings R1, R2, R3. With the
inventive bracket 1 and the uniform transfer of clamping force F
onto the cooling rings R1, R2, R3, the layer of paste P is not
forced out from underneath the cooling rings.
[0041] With only a single fastener 4, it is possible to reliably
press three (or more) cooling rings R1, R2, R3 onto the bearing
ring surface 30, so that the cooling rings R1, R2, R3 can
effectively cool the bearing ring 30. Of course, the bracket design
can equally be applied to hold one or two cooling rings in place on
the bearing ring.
[0042] FIG. 2 shows a perspective view of the cooling ring bracket
1 of FIG. 1 from above. The diagram shows how the bracket 1 might
be constructed. Here, the bracket 1 is formed by injection moulding
to comprise an arrangement of side faces 16 and intersecting
upright faces, and a cylindrical through-opening 14 that will
receive the fastener 4. The diagram also shows the upper surface 11
in the form of an annular face. To effectively transfer the
clamping force F into the body of the bracket 1, this annular face
is at least as wide as the flange 400 of the fastener head 4.
[0043] The diagram also shows an attachment strut 12 which can be
used to attach another object to the bracket 1, for example a
sensor cable can be secured to the bracket 1 by means of a cable
tie.
[0044] FIG. 3 shows, from below, a perspective view of the cooling
ring bracket 1 of FIGS. 1 and 2. The diagram shows the flat lower
surface 10 of the bracket 1, and two noses 13, 15 that will fit on
either side of the outermost cooling ring R3. The diagram also
indicates the through-hole 14 and the attachment strut 12.
[0045] FIG. 4 shows a portion of a main bearing 3 that might be
installed in a wind turbine, for example between the outer rotor
and inner stator of a direct-drive generator. The diagram shows two
sets of three cooling rings R1, R2, R2 arranged on an inner surface
30S of the inner (stationary) bearing ring 30. The cooling
arrangement may be realized as two separate cooling circuits that
are usually operated simultaneously, and so that one of the cooling
systems can be switched off during curtailed operation of the wind
turbine. To provide optimal cooling during curtailed operation, the
cooling rings are interconnected in a suitable manner, for example
the first cooling circuit includes two cooling rings of a first set
and one cooling ring of the other set, and the second cooling
circuit includes the remaining cooling rings.
[0046] The cooling rings R1, R2, R3 are pressed onto the bearing
ring 30 by brackets 1 as described in FIGS. 1 to 3. The brackets 1
are arranged at intervals. For example, for a main bearing with a
diameter of about 4.5 m, there may be 70 or more cooling ring
brackets 1 evenly distributed about the inner circumference of the
inner bearing ring 30. Because of the advantageous geometry of the
inventive bracket 1, all three cooling rings R1, R2, R3 remain
reliably pressed against the bearing ring 30, even when subject to
temperature variations and vibrations, so that efficient cooling of
the bearing 3 is ensured.
[0047] The diagram also shows a number of inlet and outlet hoses 20
attached to the cooling rings R1, R2, R3 so that a fluid coolant
can be pumped through the cooling rings. Other components of the
cooling arrangement 2 such as a pump, heat exchanger, control unit
etc. are not shown here for the sake of clarity, but may be assumed
to be part of the cooling arrangement 2. The inventive bracket 1
allows micro-movements MM of the cooling rings R1, R2, R3 during
operation of the bearing, as indicated by the short double-pointed
arrows. Such micro-movements can arise from thermal
expansion/contraction, vibration of the bearings, etc. By
permitting these micro-movements, the bracket 1 allows the cooling
rings to move slightly in both directions, so that a cooling ring
will be able to return to its original position. This is in
contrast to the known assemblies, in which a cooling ring will move
slightly in one direction but be prevented (because of a cold weld
or a high friction coefficient) from returning to its original
position, so that fasteners become loose, and the cooling hose
attachments may be damaged.
[0048] The diagram also shows a sensor cable 21 secured to an
attachment strut of a bracket 1 by means of a cable tie 22. The
sensor can be a temperature sensor, a vibration sensor, or any
other appropriate sensor used to monitor a condition in or near the
bearing.
[0049] FIG. 5 shows a known bracket 7 used to hold three cooling
rings R1, R2, R3 in place against the inner bearing ring 30 of a
main bearing 3. The known bracket 7 is a flat metal bracket 7 that
is held in place by a fastener 70 that is screwed into the body of
the bearing ring 30. The fastener 70 must be tightened to achieve a
clamping force that is sufficiently great to also press the outer
ring R3 onto the bearing ring 30. However, this clamping force may
be so high that the thermal paste P is forced out from between the
bearing ring and a cooling ring. A fragmented paste layer can
significantly reduce the effectiveness of heat transfer from the
bearing to the cooling rings. A disadvantage of this known bracket
7 is that friction between the bracket 7 and a cooling ring R1, R2,
R3 can cause a cold weld to develop, so that the cooling ring R1,
R2, R3 can only move in one direction relative to the bracket 7, as
shown be the arrow. When the cooling ring R1, R2, R3 moves slightly
because of vibrations in the bearing and/or because of thermal
expansion/contraction, it can pull on the bracket 7, so that
eventually the fastener 70 may become loose. The effect of the
loosened fastener 70 is shown in FIG. 6. Here, the bracket 7 can no
longer exert enough pressure on the outer cooling ring R3, which
can detach from the bearing ring 30, thereby reducing the cooling
performance. The bearing may eventually overheat and damage may
ensue.
[0050] FIGS. 7-9 show other possible embodiments of the inventive
bracket 1. In FIG. 7, the bracket 1 is shaped to span four cooling
rings R1-R4, and the through-hole 14 is arranged in the centre of
the bracket 1 so that the fastener 4 extends into the bearing ring
31 between rings R2, R3. In FIG. 8, the bracket 1 is shaped so that
the through-hole 14 is arranged to one side of the bracket 1. In
FIG. 9, the bracket 1 is shaped to span several cooling rings R1,
R2, R3, and the through-hole 14 extends sideways through the
bracket 1 so that the fastener 4 is screwed into a threaded bushing
on a side wall or flange of the bearing.
[0051] Although the present invention has been disclosed in the
form of preferred embodiments and variations thereon, it will be
understood that numerous additional modifications and variations
could be made thereto without departing from the scope of the
invention.
[0052] For the sake of clarity, it is to be understood that the use
of "a" or "an" throughout this application does not exclude a
plurality, and "comprising" does not exclude other steps or
elements.
* * * * *